| Message ID | 20190618143110.6720-8-deepa.kernel@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Jun 18, 2019, at 8:31 AM, Deepa Dinamani <deepa.kernel@gmail.com> wrote: > > ext4 has different overflow limits for max filesystem > timestamps based on the extra bytes available. > > The timestamp limits are calculated according to the > encoding table in > a4dad1ae24f85i(ext4: Fix handling of extended tv_sec): > > * extra msb of adjust for signed > * epoch 32-bit 32-bit tv_sec to > * bits time decoded 64-bit tv_sec 64-bit tv_sec valid time range > * 0 0 1 -0x80000000..-0x00000001 0x000000000 1901-12-13..1969-12-31 > * 0 0 0 0x000000000..0x07fffffff 0x000000000 1970-01-01..2038-01-19 > * 0 1 1 0x080000000..0x0ffffffff 0x100000000 2038-01-19..2106-02-07 > * 0 1 0 0x100000000..0x17fffffff 0x100000000 2106-02-07..2174-02-25 > * 1 0 1 0x180000000..0x1ffffffff 0x200000000 2174-02-25..2242-03-16 > * 1 0 0 0x200000000..0x27fffffff 0x200000000 2242-03-16..2310-04-04 > * 1 1 1 0x280000000..0x2ffffffff 0x300000000 2310-04-04..2378-04-22 > * 1 1 0 0x300000000..0x37fffffff 0x300000000 2378-04-22..2446-05-10 > > Note that the time limits are not correct for deletion times. > > Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> > Cc: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Andreas Dilger <adilger@dilger.ca> > Cc: linux-ext4@vger.kernel.org > --- > fs/ext4/ext4.h | 4 ++++ > fs/ext4/super.c | 16 ++++++++++++++-- > 2 files changed, 18 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 1cb67859e051..3f13cf12ae7f 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -1631,6 +1631,10 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) > > #define EXT4_GOOD_OLD_INODE_SIZE 128 > > +#define EXT4_EXTRA_TIMESTAMP_MAX (((s64)1 << 34) - 1 + S32_MIN) > +#define EXT4_NON_EXTRA_TIMESTAMP_MAX S32_MAX > +#define EXT4_TIMESTAMP_MIN S32_MIN > + > /* > * Feature set definitions > */ > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 4079605d437a..0357acdeb6d3 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -4035,8 +4035,20 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > sbi->s_inode_size); > goto failed_mount; > } > - if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) > - sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2); > + /* i_atime_extra is the last extra field available for [acm]times in > + * struct ext4_inode. Checking for that field should suffice to ensure > + * we have extra spaces for all three. > + */ > + if (sbi->s_inode_size >= offsetof(struct ext4_inode, i_atime_extra) + > + sizeof(((struct ext4_inode *)0)->i_atime_extra)) { > + sb->s_time_gran = 1; > + sb->s_time_max = EXT4_EXTRA_TIMESTAMP_MAX; > + } else { > + sb->s_time_gran = 0; > + sb->s_time_max = EXT4_NON_EXTRA_TIMESTAMP_MAX; > + } > + > + sb->s_time_min = EXT4_TIMESTAMP_MIN; > } > > sbi->s_desc_size = le16_to_cpu(es->s_desc_size); > -- > 2.17.1 > Cheers, Andreas
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 1cb67859e051..3f13cf12ae7f 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1631,6 +1631,10 @@ static inline void ext4_clear_state_flags(struct ext4_inode_info *ei) #define EXT4_GOOD_OLD_INODE_SIZE 128 +#define EXT4_EXTRA_TIMESTAMP_MAX (((s64)1 << 34) - 1 + S32_MIN) +#define EXT4_NON_EXTRA_TIMESTAMP_MAX S32_MAX +#define EXT4_TIMESTAMP_MIN S32_MIN + /* * Feature set definitions */ diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 4079605d437a..0357acdeb6d3 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4035,8 +4035,20 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) sbi->s_inode_size); goto failed_mount; } - if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) - sb->s_time_gran = 1 << (EXT4_EPOCH_BITS - 2); + /* i_atime_extra is the last extra field available for [acm]times in + * struct ext4_inode. Checking for that field should suffice to ensure + * we have extra spaces for all three. + */ + if (sbi->s_inode_size >= offsetof(struct ext4_inode, i_atime_extra) + + sizeof(((struct ext4_inode *)0)->i_atime_extra)) { + sb->s_time_gran = 1; + sb->s_time_max = EXT4_EXTRA_TIMESTAMP_MAX; + } else { + sb->s_time_gran = 0; + sb->s_time_max = EXT4_NON_EXTRA_TIMESTAMP_MAX; + } + + sb->s_time_min = EXT4_TIMESTAMP_MIN; } sbi->s_desc_size = le16_to_cpu(es->s_desc_size);
ext4 has different overflow limits for max filesystem timestamps based on the extra bytes available. The timestamp limits are calculated according to the encoding table in a4dad1ae24f85i(ext4: Fix handling of extended tv_sec): * extra msb of adjust for signed * epoch 32-bit 32-bit tv_sec to * bits time decoded 64-bit tv_sec 64-bit tv_sec valid time range * 0 0 1 -0x80000000..-0x00000001 0x000000000 1901-12-13..1969-12-31 * 0 0 0 0x000000000..0x07fffffff 0x000000000 1970-01-01..2038-01-19 * 0 1 1 0x080000000..0x0ffffffff 0x100000000 2038-01-19..2106-02-07 * 0 1 0 0x100000000..0x17fffffff 0x100000000 2106-02-07..2174-02-25 * 1 0 1 0x180000000..0x1ffffffff 0x200000000 2174-02-25..2242-03-16 * 1 0 0 0x200000000..0x27fffffff 0x200000000 2242-03-16..2310-04-04 * 1 1 1 0x280000000..0x2ffffffff 0x300000000 2310-04-04..2378-04-22 * 1 1 0 0x300000000..0x37fffffff 0x300000000 2378-04-22..2446-05-10 Note that the time limits are not correct for deletion times. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: linux-ext4@vger.kernel.org --- fs/ext4/ext4.h | 4 ++++ fs/ext4/super.c | 16 ++++++++++++++-- 2 files changed, 18 insertions(+), 2 deletions(-)